The social media highlights of the UK election

As voters decide who to vote for in the U.K.'s May 7 general election -- which analysts say is just too close to call -- the use of social media as grown in prominence.

Here are some of the highlights from the campaign so far:

1) #Milifandom

Ed Miliband, leader of the U.K. opposition Labour Party, joined the unlikely ranks of Justin Bieber and One Direction enjoying "fandom" status on Twitter earlier in April. It started after a 17-year old student, who calls herself Abby, started using the hashtag "#milifandom." The original tweet sparked something of a Twitter storm, with Abby's followers soaring to over 17,000, as #milifandom trended, with scores of young women expressing their adoration for Miliband.

Not to be outdone on the Twittersphere, young supporters of British Prime Minister and Conservative Party Leader, David Cameron, responded to #milifandom with the hashtag "#cameronettes." According to British media reports, the initial idea came from a 21-year old university student and Conservative Party supporter who said it was only meant to be an "inadvertent joke."

The Green Party made its social media mark on YouTube, with its "Change the Tune" political broadcast that depicts the leaders of the main political parties as members of a boy band. Bournemouth University Associate Professor, Darren Lilleker, an expert in political communication, said the political video was the first to go "viral" in the U.K. It has been viewed more than 770,000 on YouTube – well above broadcasts from other major parties.

For some it was the highlight of the televised challenger's debate – a hug between the three female party leaders at the end of the event did not go unnoticed on social media. Tweets, with images of the three female leaders hugging as opposition leader Miliband looked on, made a splash. Some commentators said the group hug marked the emergence of more "cuddlier" style to British politics.

She may not have reached the dizzying heights of Twitter fandom, but analysts said Scottish National Party (SNP) Leader, Nicola Sturgeon, is the politician who has so far had the most impact on social media in this election campaign. The day after April 2 seven-way leaders' debate, Sturgeon tweeted that she had gained 15,000 new followers on Twitter.

Kevin Read, chairman of digital, corporate and brand at marketing firm Bell Pottinger, said analysis of social media data showed that the SNP had gained the most in terms of sentiment following an April 16 challengers' debate that excluded the prime minister.

"The SNP had the biggest drop in negative sentiment following that debate, from about 54 percent to 47 percent, which is significant," Read said.

"When someone comes out positive on social media they can dramatically shift negative opinions of them, and if you overlay that shift over Nicola Sturgeon and her party in the broader polls, you see a solid base there was boosted by the April 16 debate," he said.